Can we optimize biomonitoring?

Biomonitoring is an element of environmental management that must become more sophisticated to meet the demands of legislation and public concern for environmental safety. Data collection and analysis techniques must improve if environmental scientists are to take full advantage of the information content of field and laboratory biomonitoring efforts. Issues associated with biomonitoring, which we address, include test system selection and the data characteristics of various biomonitoring techniques. We identify optimization as a possible approach to resolving conflicts between legal defensibility, scientific accuracy, and the requirements of environmental managers.     

我国非点源负荷研究中的问题探讨

在非点源研究实践和查阅大量非点源文献的基础上,总结出我国非点源负荷估算中通常使用的4种方法,即断面实测总负荷减去统计的点源负荷法、单位负荷法、水文线分割法和SWAT模型估算法.分析对比了这些方法在我国和北美地区使用条件的不同和使用过程中的差异,讨论了这些方法在使用中可能产生的错误.研究结果表明,在我国目前情况下前3种方法会相当程度地高估非点源负荷量,而SWAT模型在我国的应用没有充分体现其"分布式"模型的特点;同时,由于北美和中国的情况存在较大差异使得北美地区不同土地使用方面的校正数据在中国并不可用,导致在径流模拟方面也存在很大误差,因此,负荷计算将产生更大误差.在此讨论基础上,提出了在我国农业非点源负荷研究中需注意的若干问题,并结合目前我国环境现状,提出了对国内非点源污染研究和控制的见解.     

THE EFFECTS OF CLIMATE CHANGE AND IRRIGATION ON CRITERION LOW STREAMFLOWS USED FOR DETERMINING TOTAL MAXIMUM DAILY LOADS1

ABSTRACT: This paper addresses the possible impacts of global climate change on low streamflows in the Midwest, both directly, through lower precipitation, and indirectly, by rendering irrigation profitable in areas where it has found little application in the past. In the analysis presented here, streamflow data are altered to represent the effect of climate change and stream-supplied irrigation, and then used to estimate new values for two low-flow criteria, the one- and seven-day-ten-year low flows (₇Q₁₀ and ₁Q₁₀) under 20 climate change and irrigation scenarios. Additionally, the frequencies of violation of these two criteria, and multiple violations in a three-year period, are determined. Results show that the potential impact of the assumed climate change scenarios on low flow standards is substantial. A 25 percent decrease in mean precipitation results in a 63 percent reduction in design flow, even in the absence of irrigation. With irrigation, the reduction can be as much as 100 percent. The frequency of single violations of low flow criteria is found to increase several fold with irrigation. The frequency of multiple violations of low flow criteria in a three-year period is sensitive to climate change, increasing from around 20 percent to nearly 100 percent as the climate change becomes more severe.